Radon Resources
There are many fine websites that discuss all aspects of radon gas, its affect on humans, testing methods, acceptable radon levels and remediation procedures and contractors. Many state agencies offer information specific to its area.
The following links may provide answers to many questions:
General information from the EPA:
The EPA also provides useful information by county.
The New York Department of Health has a good consumer information website: https://www.health.ny.gov/environmental/radiological/radon/mitigation/what_is_mitigation.htm
The New Jersey Department of Environmental Protection website: https://www.nj.gov/dep/rpp/radon/radontes.htm
Indoor Air Quality - consumernotice.org